S. Ikeda et al., TEM studies of the microstructure evolution in plasma treated CVD TiN thinfilms used as diffusion barriers, SOL ST ELEC, 43(6), 1999, pp. 1063-1068
In semi-conductor technology, TiN thin films elements are used as diffusion
barriers between a copper interconnect layer and a silicon oxide dielectri
c. Plasma treatment application, by modifying the film microstructure, can
improve the film barrier properties and its electrical conductivity. But de
tails of the plasma application effect on the film microstructure evolution
and correlations of this evolution with the physical properties are still
unclear. To clarify the correlations, the microstructure of a series of TiN
thin films deposited using an OMCVD (organometallic chemical vapor deposit
ion) technique has been analyzed by transmission electron microscopy (TEM).
The films were obtained by cycling a basic synthesis sequence including fi
rst a limited film growth and then application of a N-2/H-2 gaseous plasma
with various powers and duration times. Films are actually stackings of pla
sma-treated elementary layers. TEM analyses show that films are made of nan
ocrystallites and that whereas no texture is observed when no plasma is app
lied, short-time plasma treatment induces a tendency to (100) texture and i
f treatment is longer, the direction of texture progressively rotates to (1
10). A tentative interpretation of this texture evolution has been made in
terms of nucleation and growth and correlations between this evolution and
the effect on the physical properties have been obtained. (C) 1999 Elsevier
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